Power devices employing impact ignited low explosive



Sept. 30, 1969 R, KVAVLE ET AL 3,469,757

POWER DEVICES EMPLOYING IMPACT IGNITED LOW EXPLOSIVE Filed Nov. 9. 1966 4 SheetS-Sheet 1 el QUI a 8 Z .Z 0 V/ r w w w E ab@ M n C L. D W e d A v im m s n e ik 7@ m n mmm www .A NQS u ,w N www@ m L /l/f- NN N; NN hm. Sw .Xn j Hld Nw www@ E ww l a @www bw .P 7 QZ a J/ o V Ar/f/.`f Sw mm am L/\\\\\ W a w i N d y J/ s a, www m .2 a, w v m SJ mw www H wm. A :um

sept. 30, 1969 R, Q KVAVLE ET AL 3,469,757

POWER DEVICES EMPLOYING IMPACT IGNITED LOW EXPLOSIVE 4 Sheets-Sheet ."2 v

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Filed Nov. 9. 196e Sept. 30, 1969 RI C, KVAVLE ET AL 3,469,757

POWER DEVICES EMPLOYING IMPACT IGNITED LOW EXPLOSIVE Filed Nov. 9. 1966 4 Sheets-Sheet 3 Sept. 30, 1969 R C, KVAVLE ET AL 3,469,757

POWER DEVICES EMPLOYING IMPACT IGNITED LOW EXPLOSIVE I Filed NOV. 9. 1966 4 Sheets-Sheet 4 F@ 910 XH /w rates Patent ffice 3,469,757 Patented sept. ao, 1969 ABSTRACT F THE DISCLOSURE This invention relates to explosively actuated devices, and more especially to hand-held tools of this type wherein there is alined, on an axis of the barrel bore, an axially movable chamber for receiving an explosive charge, and firing mechanism for impacting the charge to drive a fastener by means of expanding gases.

Claims While the the invention is herein illustrated as embodied in a single shot tool of the type wherein a gas pressure operated piston is adapted to drive fasteners such as studs or the like, and preferably employs a solid low explosive charge to be actuated by impact and without the use of a detonator, it will be understood that in various aspects the invention is not thus limited in use nor in the particular features of construction herein shown merely by way of example.

There is disclosed in United States application Ser. No. 371,242, filed May 29, 1964, upon application of Robert C. Kvavle (now U.S. Patent No. 3,283,657), a unique method and means for initiating deilagration in a solid low explosive. They involve impacting the charge in a substantially closed chamber thereby crushing at least a portion of the charge and f rictionally generating internally the heat required for ignition. In this manner precompression of air surrounding the charge is not relied upon to elevate temperature for the purpose of ignition, and hence ignition is safely attained with expenditure of less energy.

Another United States application, Ser. No. 524,168, filed Feb. 1, 1966, in the name of Robert C. Kvavle (now US. Patent No. 3,372,643) describes and claims a formed charge of low explosive preferably of fibrous nitrocellulose, desirable for use in impact ignition devices as herein disclosed. Aside from the advantageous features of added safety, relative simplicity, and ease of ignition thereby afforded, resulting deflagration of the novel charge according to the method cited occurs effectively to generate explosive gases leaving very little or no residue and having remarkably low, if any, corrosive effect.

It is a primary object of this invention to provide an improved impact-actuated device of simple construction and safe, reliable design which shall employ the novel method mentioned and a primerless solid, low explosive propellant.

A further object of this invention is to provide, an an explosively actuated fastener driving tool of the type having a fluid pressure driven ram operative by combustion of a solid, low explosive, a mechanism requiring the expenditure of only a moderate amount of manual energy for cocking the tool.

Another object is to provide, in a device of the type indicated, means whereby it may be conveniently breech loaded with successive case-less, primer free charges to be exploded, and a charge readily unloaded in the event of non-fire or misre.

To these ends, and in accordance with a feature of the invention, the illustrative tools comprise a barrel having a breech end wherein a substantially closed firing chamber is defined on one side by an anvil having vents arranged to be sealed by a charge prior to and during ignition, and on the opposite side by firing mechanism including a charge impacting pin and a charge containing member. For purposes of convenient breech loading, either front end breech loading in one embodiment, disclosed in copending application Ser. No. 564,654, filed July 12, 1966 now abandoned, or rear end breech loading in an alternate form of the invention, the barrel is axially slidable in a tool housing to an open or loading position, much as in the manner disclosed for example in United States Letters Patent No. 3,168,744, issued Feb. 9, 1965, on an application filed in the name of Robert C. Kvavle, and relating to a cartridge-tired tool. Also, the tools of the present invention to be described preferably resemble the tool disclosed in the last-mentioned patent in several other respects, one of which is that cooking is accomplished by pressing the muzzle of the barrel against an abutment or work piece and relatively advancing the housing axially. Conventional explosively actuated tools use one spring for operating a striker and a second spring for repositioning an action; cumulative resistance of these springs must be overcome in cocking such tools. Since a striker spring for impacting solid, low explosive must itself be quite powerful to effect ignition, a further feature of the present invention resides in providing mechanism for eliminating the action repositioning spring and hence its resistance to cocking. By novel means herein shown, safe cocking is attained, a sear of the ring mechanism being adavntageously used to transfer striker spring load to an action which is axially movable by the barrel, but readily disconnectable therefrom, as will be explained.

A further feature is to be recognized in an alternate form of the invention wherein breech block mechanism, relatively movable toward and from the breech end of a barrel to dene a firing chamber and confine therein a charge to be impact exploded by a ring pin, has a shroud slidably carrying the firing pin and is fixedly mounted in the breech block for telescoping relation with the breech end of the barrel, an end of the shroud being recessed to receive and hold the charge whereby, prior to completion of its dellagration, it coacts with the shroud to seal off the chamber from the bore of the barrel.

The foregoing and other features of the invention, together with various novel details in construction and combination of parts, will now be more fully described in connection with two illustrative embodiments, and with reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal section of a hand-held explosively actuated tool for driving fasteners or the like, the tool being in cocked to fire position;

FIG. 2 is a view similar to FIG. l but with parts shown at a later stage in a cycle of operation, after the tool has been fired, and with its barrel still connected to an action;

FIG. 3 is a view similar to FIGS. 1 and 2 but indicating a later stage when the barrel has been disconnected from the action and moved to open or reloading position;

FIG. 4 is a view corresponding to FIGS. 1-3 but showing the parts at a still later stage when the tool has been reloaded with a charge and partly muzzle loaded with a fastener, the tool now being prepared for recocking;

FIG. 5 is a transverse section taken on the line V-V in FIG. 1;

FIG. 6 is a transverse section taken on the line VI-VI of FIG. l;

FIG. 7 is a partial transverse section showing an alternate form of anvil having external vents;

FIG. 8 is a longitudinal section of a portion of a tool similar to that of FIGS. 1-7 but embodying an alternate form of the invention facilitating loading and unloading, the tool being in cocked to fire position;

FIG. 9 is a longitudinal section largely corresponding to FIG. 8 but showing the tool in its opened condition for rear breech loading or unloading;

FIG. l() is an enlarged transverse section taken on the line X-X of FIG. 8; and

FIG. 11 is an enlarged transverse section taken on the line XI -XI in FIG. 8.

The front end breach loading tool of FIGS. 1 6 comprises a barrel housing one end of which is secured in an axial aligned tubular portion of a gripy assembly 12 (FIGS. 1 4). In order to afford easy access to a barrel 14 axially slidable in the housing 10, the housing 10 is formed with an opening 16. Except as may be noted and in the novel aspects hereinafter to be explained in detail, it may be assumed that the illustrative tool largely corresponds to that fully disclosed in the aforementioned Patent 3,168,744 and hence normally may include a fastener driving ram 18 having a piston head 20 provided with a friction ring 22 engageable with the interior wall of the barrel 14. An end of the ram 18 is received in a guide 24 slidably positioned in the muzzle end of the barrel and adapted to receive a fastener, for instance a stud 26, to be driven.

Threadedly secured to the breech end of the barrel 14 is an adaptor (FIGS. 1 4) arranged removably to position an anvil 32 at one side of a firing chamber. The anvil preferably has a raised portion 34 for facilitating impact ignition thereagainst of a charge 36 (FIG. 3) of solid low explosive, preferably in the reversible end-forend pellet form as disclosed in U.S. application Ser. No. 524,168 referred to above. When the ring chamber has been loaded and the tool cocked as later described, a circular series of axial vents 3S in the anvil 32 will be closed by the charge 36 as shown in FIG. l, the charge being seated in and peripherally contained by, a power sleeve 40 which, for a purpose later mentioned, is removably mounted. The other side of the firing chamber from the anvil 32 is sealed by a tubular holder 42 telescoped in the sleeve 4t)v and an axially slidable firing pin 44 in the holder, an enlarged collar 46 of the pin being slidably retained in an enlarged bore 48 formed in the holder by means of an insert 50 threaded into one end of an action 52. It will be apparent that the firing chamber is thus adapted to receive charges 36 of fixed diameter substantially corresponding to the internal diameter of the power sleeve 4t), and that the axial length of the charge may be selected according to whether greater or less power output is required. The sleeve 40 is designed to engage the anvil 32 endwise regardless of the selected axial length of the charge 36, a friction ring 54 (FIG. 3) detachably retaining the power sleeve 40 in the barrel adaptor 30.

Firing mechanism next to be explained comprises a striker 56 slidable within the action 52, a striker spring 58 one end of which abuts the bottom of an internal recess 60 in the grip assembly 12 and the other end of which is seated in the striker 56, a sear 62 nested in a transverse bore 64 in the striker, and a trigger 66 pivotally mounted at 68 in the grip assembly 12. With the muzzle of the barrel engaging an abutment, for instance a surface S (FIG. 1) into which the fastener is to be driven, the striker spring 58 is held compressed, when the tool is cocked, by means of an enlarged end 70 of the sear 62 extending for engagement with the wall of a slot 72 of the action under the iniiuence of a spring 74 nested between a collar 76 of the scar and a shoulder of the bore 64. A leaf spring 78 having one end abutting an internal wall of the assembly 12 has its other end arranged to bias the trigger 66 clockwise as shown in FIGS. 1-4, to inoperative position. Accordingly, to initiate ignition and hence deflagration of charge 36 for firing the tool, the trigger 36 is pulled and thus pivoted counterclockwise against the resistance of the spring 74 to free the sear end 70 from the action slot 72. Hence potential energy of the spring 58 is used to cause the striker 56 rapidly to advance and, through an axial blow on the firing pin 44, to impact the charge 36, the gases of combustion passing through the vents .38 to operate the ram 18 and thereby drive the fastener 26. As the striker 56 moves forwardly, the sear end 70 rides on the inside wall of the action 52 but cannot enter a vent hole 80 which merely allows air in the action to escape through the barrel housing 10.

In order to reset the scar 62 for the next shot, the barrel and its adaptor 30 are operatively connected to the action 52 as will next be described. After the tool has been fired and is to be readied for reloading by pulling the barrel 14 forwardly relatively to its housing 10, the striker 56 is prevented from moving any further forward, except to a very limited extent. This is because an end 82 of the Sear now engages an inner end of a screw 84 (FIG. 2) threaded into and projecting radially within the barrel housing 10. In pulling the barrel 14 forwardly to open the breech (as shown in FIG. 3) for reloading preparatory to resetting the sear 62, the action S2 is thus caused to be moved further forwardly relative to its now axially restrained striker 56 by reason of a barrel-controlled releasable interconection between the adaptor 3G and the action. This interconnection or locking system preferably, as shown in FIGS. 1, 2, 5, is in the form of a plurality of axially extending, segmental locking levers 86 which, in their connecting position, are disposed about a portion of the circumference of the adaptor. Each of the levers 86 may constitute a one-quarter or a one-third segment of a machined ring from which they are respece tively cut. For pivotally connecting one end of the respective levers 86 to the action, a wire 88 (FIG. 5) is looped about the action 52 and extends through an external groove formed on the rearward ends of the levers 86. Forward ends 90 of the levers 86 may frictionally engage a recessed external wall 92 of the adaptor. The ends 90 are then urged radially outward partly by reason of the wire S8 tending to pivot the levers on a collar of the adaptor 30, and partly by a resilience in the ends 90 when an intermediate fulcrum portion 96 of the levers 66 engages an inside wall 98 of the housing 10.

In the course of advancing the action 52 by the barrel pull exerted through the locking levers 86, the action slot 72 is axially advanced relatively to the restrained sear 62 until the latter, by reason of the compressed sear spring 74, has its end 82 released from the screw 84 and the opposite sear end 70 reseatcd in the action slot 72. Now the striker 56 is further urged forwardly by its spring 58, and the action 52 is consequently yieldably held in a forward position wherein the forward ends 9i) of the locking levers 86 disengage from the adaptor 30 and radially spring open into relaxed position in an internal recess 99 in the barrel housing 10 as shown in FIG. 3. The barrel 14 is thus disconnected or unlocked from the action 52 as soon as the fulcra 96 move into the recess 99, and may be moved further forwardly until a safety key 100 (FIG. 3) engages an end of a barrel housing slot 102. The ram 18 was, of course, advanced during the prior firing of the tool, and a conical mouth 104 of the power sleeve 40 may now receive the next propellant pellet 36 (FIG. 3) to be exploded, the pellet being introduced through the opening 16, and the friction ring 54 insuring that the sleeve was retracted along with the adaptor 30 to this easily accessible reloading position.

At reloading, the tool usually being held muzzle down for this purpose, the pellet 36 will normally readily descend by gravity to seat itself properly over the central anvil igniter portion 34. The charge 36 may be reversible end-for-end and have a thin intermediate web portion which is thus in close proximity to the anvil igniter portion 34. lf for some reason the prior charge 36 had failed to ignite, the sleeve 40 may be withdrawn from the adaptor 30 along with the faulty pellet. To extract such a pellet the sleeve is then pressed over a pin and the low explosive pellet safely dislodged. After reassembly of the sleeve 40 in the adaptor and reloading of the charge, and since the key 1%() is engaged in the guide 24 and has accordingly moved the guide inwardly in the barrel 1d as shown in FIG. 3 (by reason of the prior leftward ad vancing movement of the barrel) for endwise contact with the ram head 20, the stud 26 may be thrust into the muzzle end of the barrel preparatory to cocking, as indicated in FIG. 4. A spring-pressed plunger 166 in the barrel housing 1t) and backed by a screw 103 in a guidewa'y 110 secured to the housing 1b serves, when the barrel 14 is vertically slidable, to frictionally engage it and prevent its premature advance movement until the plunger is displaced outwardly by a cam 112 formed on the adaptor 30.

To cock the tool the muzzle of the barrel is pressed against an abutment, normally that surface S (FIG. l) into which the fastener is to be driven, the barrel housing and grip assembly 12 being forced to the left as shown in FIG. 1. This causes the barrel assembly to be closed, i.e., the barrel 14, its ram 15, the adaptor 3i), the anvil 32 the power sleeve dit and its charge 36 reenter the locking system with the ends 96 of the locking levers 86 restored to their captured positions against the wall 92. as the action 52, now reconnected to the adaptor 3i?, is moved relatively to the right. This compresses the striker spring 5S until the sear 62 is again in cock to fire position with respect to the trigger 66.

It should be noted that if the pellet 36 when first loaded into the mouth 1012i of the sleeve 46 did not ini tially seat on the igniter 3d of the anvil, the cooking n movement of the sleeve causes the holder d2 to be axially received thereby urging the pellet into proper position on the anvil 32.

If, as in the conventional explosive device of this genJ eral type, a compression spring for repositioning the action 52 and resetting the sear 62 had been required in addition to the striker spring 58 (which by itseif needs to be quite powerful for impacting solid, low explosive), the total force required for cooking would probably be in excess of what would generally be acceptable in a hand-held tool. The uncomplicated construction described obviates the second spring; it renders cocking of the tool both safe and easy by means of the described arrange ment wherein in each cycle the sear 62 is enabled rst to transfer striker spring load to the action 52, and thereafter the cocking movement of the action is enabled, through the reset sear, to reload the striker spring SS.

FIG. 7 illustrates an alternate form of anvil 114i` which may be used in lieu of the anvil 32. The anvil 114, instead of having internal vent holes 38 circular in section, is formed with opposed external cutouts 116, thus defining, with the internal bore of the adaptor Sti, two relatively large exhaust ports respectively having opposed or double convex walls. It is believed that for the same output the greater surface area thus exposed to the same volume of ported gases of combustion would incur less erosive effect than the circular bores 38. A- further advantage of such an externally ported anvil 114 is that it is subjected to lower stress concentration by reason of the larger dimension afforded between the vents, thus reducing fatigue cracking in the port walls. It will be understood that the power sleeve 4h blocks the two exhaust ports until sufficient gas pressure develops to blow it back from the anvil 114, thus improving burning of the charge.

An alternate construction shown in FIGS. 8-l1 inclusive, which may be termed a rear or breech block loading arrangement in contrast to the front breech loading structure described above with reference to FIGS. 1-7 inclusive, will next be explained and its relative advantages indicated. It will be noted that the power sleeve 4() is not included, and that a bolt, sleeve or shroud 126 (FIGS. 8, 10) slidably carrying a firing pin 122 has a force I'it or is otherwise fixedly secured in an end of an action 124. As shown in FIG. 8, the shroud 126 has a forwardly projecting portion for telescoping with the breech end of a barrel adaptor 126 (taking the place of the adaptor 30 in FIGS. 1-4) when the tool is in breech closed condition. The forward end of the shroud is formed with an axial recess to provide a mouth 128 which is readily accessible in breech open condition and slightly tapered axially for receiving a charge 130, such as the pellet 36, to be exploded.

An anvil 132 (FIGS. 8, 10) is retained between an end of the barrel 14 and the adaptor 126. When the tool has its breech closed and the tool has been cocked in the same manner above described, the anvil 132 defines one side of a substantially closed firing chamber. In this case, for a reason to be mentioned, a central protrusion 134 of the anvil extending toward the breech is preferably more pronounced than the previously mentioned raised anvil portion 34. During breech closure the mouth 128 of the shroud, backed by the resistance of the spring 58, axially cooperates with the relatively retracting anvil 132 to press the charge 130 tightly into the tiring chamber between confronting faces of the shroud or mouth 123 and of the anvil protrusion 134. It will thus be seen that, regardless of the axial dimension of the charge (and it is contemplated to provide different power levels by grading this dimension in charges having constant diameters and substantially constant composition), the arrangement is such that a lip of the shroud 12b serves with the axially compressed charge itself to seal off the firing chamber from a pair of arcuate anvil vents 136 otherwise communicable with the bore of the barrel 1d. As best seen in FIGS. 8, 1l the bore of the mouth 123 at its wider end is only slightly larger in diameter than the diametral dimension between the respective inner walls of the vents 136. Accordingly small convex openings into the respective vents 136 are rst unsealed only when, advantageously, detlagration of the charge 13d has progressed radially under increasing pressure of the gas generated upon ignition, nearly to the point of complete consumption. The vents 136 are shaped to afford maximum porting area consistent with a strong anvil, and it is important that their inner edges at the breech end of the protrusion 134 be sharply and accurately defined to insure proper initial sealing of the vents by each charge 131B.

In order to allow for different thicknesses of charges 13), segmental locking-levers 14n (somewhat like those designated 86 in FIG. l) releasably secure the barrel 14 and an action 142 together during the ring sequence. For this purpose the levers `are confined in the bore of the barrel housing 16, front ends of the levers being urged radially inward to seat behind the flanged breech end of the adaptor 126 by a resilient elastomeric ring 144 (FIG. 8) bearing outwardly on the rearward ends of the levers 140. The function of the ring 144 is, like that of the plunger 1% in FIG. 4, to urge retention of the barrel 14. An inner pivotal shoulder 146 on the levers is axially spaced from their front ends and disposed to engage a flanged breech end of the action 124 thereby permitting clearance or take up space between the confronting end faces of the action and the adaptor, and hence accommodating pellets of different power level thickness to be exploded.

Operation of this breech block loading tool is essentially similar to that of the tool of FIGS. 1 7, and will now be briefly reviewed while explaining other minor differences in construction. Assuming the tool to be loaded and cocked as indicated in FIG. 8, the trigger 66 is pulled to release one end '7G of the sear 62 from the action slot 72 and thereby enable the compressed spring 58 to force the striker 56 forwardly for impacting the firing pin 122 and effecting ignition. After thus driving the fastener 26 from the barrel by pressure of the gas generated and escaping through the anvil to act on the piston head 20 (FIG. 8), the operator may use two hands to open the breech by relatively moving the barrel 14 forwardly with respect to the housing 1t), or he may, with only one hand on the grip portion l2, swing the tool so that the barrel is relatively extended by inertia. Such advancing movement of the barrel also resets the sear 62, the action 124 being simultaneously advanced by the locking levers 14d, but the striker 56 being almost immediately prevented from further moving forwardly by reason of engagement of an end of the sear 62 with an end 156 (FIG. 9) of a longitudinal slot in the housing 10. Accordingly, as the action 124 is moved forwardly, its slot 72 is repositioned to again receive the spring-pressed sear end 70, the striker and the action now being, in effect, reunited for unrestrained further forward movement under the influence of the spring 58. As the action 124 continues forwardly its locking levers 140 are allowed radially to open into the internal barrel recess 99 (FIG. 9), the barrel 14 then being released to move forwardly without the action 124. The latter now moves only slightly further forward as urged solely by the spring 58 until the sear end 70 abuts the forward end of a longitudinal slot 152 in the housing. This slot 152 accommodates operation of the trigger, and its forward end serves by thus engaging the sear to prevent unintended release of the action from the housing. If it is desired to disassemble the action from the tool, clockwise pivoting of the trigger 66 will cause its arm 154 to cam the Sear end 70 from the slot 152 and permit withdrawal of the action. lt will be understood that, as previously, the ram i8 is repositioned at the breech end of the barrel bore as the barrel is advanced by means of the slidable guide 24 (FIGS. 1, 2).

By comparison the breech block loaded tool of FIGS. 8-11 is usually preferred since it is of simpler structure, avoids any change of blow-by or fouling which might be permitted by the power sleeve it@ if it corrodes, enables the tool to be loaded With its charge more easily, and in the event of misfire or nonre the readily accessible charge can be easily unloaded by directly picking it from the mouth 128.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. In a device for driving fasteners and the like by means of combustion of an explosive charge, a barrel having a breech end and axially movable between open and closed positions, an anvil secured in the breech end of the barrel and having a vent affording communication between the bore of the barrel and one side of a tiring chamber, and firing mechanism for confining the charge in said chamber in position to seal off said vent during ignition of said charge, said mechanism including a charge receiving member yieldingly movable toward the anvil, and a firing pin slidable in the member for imp-acting at least a portion of the sealed oncharge against said anvil.

2. In a device for driving fasteners and the like by means of combustion of an explosive charge, a barrel having a breech end and axially movable between open and closed positions, an anvil secured in the breech end of the barrel and having a vent affording communication between the bore of the barrel and one side of a ring chamber, and firing mechanism including a tiring pin and telescoping charge holding member movable toward the anvil, the arrangement being such that the member causes a marginal portion of the charge to seal off said vent during impact ignition by the pin of an interior portion of the charge.

3. In an explosively actuated tool of the type comprising a barrel and a housing therefor relatively slidable from breech open to breech closed position to cock a spring actuated striker in the housing, a spring biased sear yieldably mounted in the striker, an action movable in the housing to carry tiring mechanism between a cocked position determined by an effective engagement of the Sear with the action and into cooperative relation with the breech end of the barrel when in said closed position, a trigger mounted in the housing for disengaging the sear from its effective engagement with the action when cocked to cause the striker to actuate said firing mechanism, and means releasably interconnecting the barrel and action, said means being effective during relative opening movement of the barrel and housing to reset the sear in the action and then release the barrel `from the action.

4. In an explosively actuated tool of the type comprising a barrel and a housing therefor relatively slidable from breech open to breech closed position to cock a spring actuated striker in the housing, a spring biased sear yieldably mounted in the striker, an action movable in the housing to carry tiring mechanism between a cocked position determined by an effective engagement of the sear with the action and into cooperative relation with the breech end of the barrel when in said closed position, ,a trigger mounted in the housing for discngaging the sear from its effective engagement with the action when cocked to cause the striker to actuate said firing mechanism, and means releasably interconnecting the barrel and action, said means being effective during relative opening movement of the barr-el and housing to reset the sear in the action and then release the barrel from the action, and effective during relative closing movement of the barrel and housing to reconnect said barrel whereby the action and the reset sear may be moved into cocked relation to the trigger.

5. A tool as set forth in claim 4 wherein the action is formed with a slot for seating an end of said sear, and an abutment is arranged in the housing for engagement with an opposite end of the Sear after firing to enable movement in unison of the action and barrel independently of the striker toward the breech open position whereby the interconnecting means is released and the sear repositioned in said slot in the action preparatory to recocking the tool.

6. A tool as set forth in claim 4 wherein said releasable interconnecting means includes at least one locking lever pivotally related to one of the barrel and the action, and means formed on the housing for rendering the locking lever effective or non-effective depending on the direction of the relative position of the barrel with respect to the housing.

7. In an explosively actuated tool of the type comprising a barrel axially slidable in a housing, an anvil carried by the barrel at its breech end, an action slidable in the housing, means releasably interconnecting the action to the breech end of the barrel, said interconnecting means being adapted to be released by relative breech opening movement of the barrel and housing and reconnected by their relative closing movement, firing mechanism movably carried by the action for impacting a charge against said anvil, means for operating said tiring mechanism including a spring pressed striker movable in the action and arranged to be energized by relatively moving the barrel and housing into breech closed relation, a trigger pivoted to the housing, a spring pressed scar in the striker engageable with a portion of the action to hold the striker energized when the breech is closed, the Sear being releasable from said action portion by operation of the trigger for actuating the tiring mechanism, and means in the housing for thereafter restraining the striker during breech opening movement of the barrel and housing to reengage the sear with said action portion preparatory to recocking.

3. In an explosively actuated tool of the type to be cocked by relatively moving a barrel and its housing into breech closed relation, an action in the housing and releasably connected to the barrel for carrying firing mechanism toward and from operative relation to said barrel, a striker slidably mounted in the action, a spring acting on the striker and energizable by the relative closing movement of the barrel and housing, a trigger releasable sear engageable with a part of the action in one position to hold said striker and spring cocked when the barrel is in closed position, means, operative after the trigger has released the sear partly to deenergize the spring and cause the firing mechanism to be operated by said striker, responsive to relative barrel movement toward breech open position for reengaging the sear with said part of the action to thereafter permit disconnection of the action from the barrel, and means on the housing for retaining the action therein when the barrel is dis.

connected.

9. A tool as set forth in claim 8 wherein means releasably connecting the breech end of the barrel and an adjacent end of the action is adapted to be disconnected by relative breech opening movement of the barrel and housing, and to be connected by their relative closing movement.

10. In an explosively actuated device of the type to be cocked by relatively moving a barrel and its housing into breech closed position, a tubular action in the housing mounted for sliding in coaxial relation to the barrel bore and having diametrically opposed first and second slots, firing mechanism carried by the action, said mechanism including a ring pin for impacting a charge conned between the breech end of the barrel bore and a telescoping breech end of the action, a spring-pressed striker slidable axially in the action, a spring pressed sear transversely disposed in the striker and having a first end engageable in said first slot in the action to hold the striker cocked, a trigger movably mounted on the housing both to release the iirst end of the sear from said rst slot to enable the striker to cause the pin to impact said charge and to move a second end of the sear into said second slot in the action, means releasably interconnecting the breech end of the barrel to the action, and an abutment in the housing for engaging said second end of the sear in said second slot and hence axially restraining the striker after said charge impacting whereby subsequent relative breech opening movement of the barrel and housing enables said iirst slot in the action to be repositioned axially for reseating said rst end of the sear therein preparatory to recocking movement of the barrel and housing.

11. In an explosively actuated tool of the type to be cocked by relatively moving a barrel and its housing coaxially into breech closed position, an action coaxially slidable in the housing for carrying firing mechanism into and out of cooperative relation to the breech end of the barrel when in breech closed position, a spring pressed striker operable in the housing for actuating said firing mechanism, sear means carried by the striker and yieldably urged into a slot in the action, a trigger on the housing movable to release the sear means from the action slot to operate said striker when the tool is cocked,

means releasably interconnecting the action to the barrel and adapted to be disconnected by breech opening movement of the barrel and said housing and reconnected by their breech closing movement, and means in the housing operable .after the striker has moved to operate the firing mechanism for restraining the striker from moving further with the action in the course of the breech opening movement of the barrel and housing whereby said slot in the action may be advanced to reseat said Sear means therein preliminary to recocking.

12. In an explosively actuated device of the type to be cocked by relatively moving a barrel and its housing into breech closed relation, an anvil mounted in the breech end of the barrel and forming one side of a firing chamber having exhaust connection with the bore of said barrel, said anvil being formed with arcuate slots having opposed convex exhaust surfaces, a spring pressed action slidable in the housing coaxially with said barrel bore, a sleeve mounted in one of the action and the barrel and extending toward the other of the barrel and the action for receiving a charge to be exploded against said anvil, and ring mechanism carried by the action and including a ring pin extending in the sleeve to confine said charge in said firing chamber prior to and during ignition in a position to block said exhaust connection.

13. A tool as set forth in claim 11 wherein said ring mechanism includes means projecting from the action for movably carrying a firing pin and for closely conning between ,an end thereof and a peripherally vented portion of said breech end of the barrel, when the tool is in breech closed condition, a charge to be impacted by said pin.

14. A tool as set forth in claim 13 wherein said tiring pin carrying means is formed with an axially tapering mouth.

15. A tool `as set forth in claim 11 wherein said means releasably interconnecting the action to the barrel is provided with axially spaced portions respectively adapted for locking engagement with the breech ends of the barrel and the action to permit their relative endwise movement to accommodate charges having different power level thickness.

References Cited UNITED STATES PATENTS 2,697,830 12/ 1954 Erickson et al. 227-11 2,731,636 1/ 1956 Bumiller 227-11 2,804,620 9/ 1957 Gannon 227-9 3,168,744 2/ 1965 Kvavle 227-10 XR 3,235,154 2/1966 Mulno 227-10 3,323,705 6/ 1967 Grotsch et al 2.27-10 XR TRAVIS S. MCGEHEE, Primary Examiner 

